On the other hand, there is no information regarding whether the microleakage of water exactly represents the microleakage of bacteria and bacterial byproducts. Cabozantinib purchase Using a test method that directly measures the bacterial penetration[22, 23] could be more convenient for the evaluation of bacterial microleakage. The FRC dowel systems tested in this study are basically epoxy polymers or methacrylates, such as bisphenol-a glycidyl methacrylate (BIS-GMA), polymethyl methacrylate (PMMA), urethane dimethacrylate (UDMA), and hexane-dion dimethacrylate (HDDMA). These polymers have chemical properties similar to the resin

cements. Therefore, a strong chemical bonding between the FRC dowels and the resin cement is expected. Doxorubicin clinical trial This is partly confirmed by this study through the better microleakage results of most of the FRC dowel groups than the stainless steel dowels; however, FRC dowel systems are usually marketed with a highly cross-linked and polymerized epoxy resin matrix.[24] Torbjörner and Fransson reported that bonding between the polymerized FRC dowel matrix and resin cement is primarily based on micromechanical characteristics, and that it is difficult to obtain chemical reactions with a highly polymerized resin dowel matrix.[25] These suggestions could explain the differences among the FRC dowel groups. More studies about the chemical interactions between the polymerized matrix and resin cement are needed. For all types of

medchemexpress mechanical and chemical bonding, surface roughness, wetting ability, and micromechanical retention related to these features are critical components. Bitter and Kielbassa reported that pretreatment of the dowel surface using hydrogen peroxide, sodium ethoxide, or potassium permanganate could enhance the bonding of resin cement by creating micromechanical retention at the dowel surface.[26] We do not have any information about the surface roughness of the dowels used in this

study. For some groups, additional dowel surface treatments, such as acid etching (HEG), bonding agent application (LEQ), and conditioning with special system components (CSG), did not create any difference. Moreover, these processes make the cementation procedure more complex and time consuming. Albashaireh et al reported that phosphoric acid etching of the glass fiber reinforced dowel surface is useless for improving the bond strength of the dowel.[27] The easy cementation procedure of the presilanated USZ group, which had results as good as the groups mentioned above, could be considered an advantage. In this study, the root canal fillings and core restorations were not made, to avoid the possible undesirable effects of these variables on the microleakage measurements. In the clinical situation, the presence of remaining apical root canal filling, core restoration and cemented crown restoration would also act as additional microleakage barriers besides the cemented dowel.